ARM: crypto: add NEON accelerated XOR implementation
Add a source file xor-neon.c (which is really just the reference C implementation passed through the GCC vectorizer) and hook it up to the XOR framework. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org>